Grease extracting ventilator for kitchen ranges



Filed Dec. 27, 1955 I N VEN TOR. KENNETH E. LUNDE 7AM/fw QM- AT'ToR/VEV2,889,007 Patented June 2, 1959 GREASE EXTRACTING VENTILATOR FOR YKITCHEN RANGES Kenneth E. Lunde, Sunnyvale, Calif., assiguor to DohrmannHotel Supply Co., San Francisco, Calif., a corporation of NevadaApplication December 27, 1955, SerialNo. 555,620

2 Claims. (Cl. 183-37) The present invention is concerned with kitchenventilators and with lthe extraction of grease from gases which arewithdrawn from the cooking area, such as the range surface or frysurface in a commercial kitchen and relates more particularly to methodsand apparatus for efficiently extracting the grease from such gases.

In the cooking of foods in commercial eating establishments,particularly in establishments such as drive-ins where the frying ofquantities of grease-containing foods occurs, the problem of extractinggrease from the gases over the cooking surface is quite severe.

In accordance with the instant invention, a process and apparatus forthe extraction of the grease from the exhaust gases from the kitchenranges is carried out in a novel and eifective manner, in a series ofsteps, and accordingly it is a general object of the invention toprovide an improved method and apparatus for the extraction of greasefrom the exhaust gases from above a cooking surface such as a range.

Another object of the invention is to provide improved apparatus of asimple structure which is in part self cleaning with respect to thegrease collected.

The above and other objects of the invent-ion are attained as describedin connection with the preferred embodiment thereof, as lillustrated inthe accompanying drawing, in which:

Figure 1 is a vertical sectional view through a grease extracting unitembodying the invention, with a portion of a cooking range shownschematically.

Figure 2 is a sectional view taken in a plane indicated by the line 2 2of Figure 1 and showing the rotor in bottom plan.

Referring to the drawing a conventional form of commercial kitchen range.is illustrated, having a cooking surface 11, and having respective sideplates 12 at each side of the cooking surface, only one of which isseen. Grease laden gases from the surface of the range are extractedthrough a slot 13 above the grease collecting trough 14 and are drawnthrough the grease extracting unit 15 and a discharge conduit or duct 16through which the gases are drawn by a conventional fan or blower 17. Ingeneral the duct 16 -is cylindrical and leads to a suitable point ofdischarge for the gases. From the top of the range a discharge conduitsection 18 is provided of substantially the same diameter as the conduit16.

Between the conduit section 18 and the duct 16 a grease extracting unit15 is arranged in which the gases are irst passed through a movableseries of grease extracting blades, at the same time that the directionof the tlow of gas is changed, so that these blades tend to gatherentrained droplets of grease, particularly the grease particles oflarger size. In the second phase of the grease extracting operation, thegrease laden gases are carried through an annular filter mounted forrotation with the grease extracting blades.

In the conduit section 18 a cross channel 19 is provided carrying at acentral point thereof an upright stationary shaft 20 which is secured atthe reduced upper 2,. end in a similar cross channel 21 placed in aconduit section or baille 22 located inside a casing 23. Shaft 20 hasjournaled thereon by means of a suitable bushing 24 a baffle orinterceptor plate 26, which is spaced from the outer wall of the casing23, which formsa conduit portion of enlarged cross-section between theconduit sections 18 and 16. From the lower surface of the plate 26 therevdepend a series of V-shaped grease extracting blades 27,4

which are disposed in angled relation about their axis of rotation. Theblades 27 act also as drive blades for the interceptor plate or wheel 26under `the influence of gases driven by the blower 17. These blades inaction tend to be self cleaning and expel centr-ifugally any droplets ofgrease collected thereon.

The tubular or cylindrical iilter unit carried by plate 26 comprises atubular shaped filter 31 of grease entraining and retaining material,carried on an inner frame surface 32 of expanded metal, and held inplace by a suitable screen 33 disposed about its outer surface. The sizeof the fibers of the lter medium -is selected with reference to thedesired particle size or droplets of grease to be collected, and servesnot only to entrain additional, grease droplets, but also catches any ofthe droplets from the blades 27, which become reentrained in the flowupwardly through the filter. The annular filter 31 also overlaps conduitsection 22, to form a seal against the direct low of gases, thecloseness of the spacing minimizing any escape of grease dropletstherethrough and back to the air stream. Drops of grease remaining inthe gases tlowing radially inwardly through the lilter 31 will be inpart repelled by the lilter and will descend in the casing 23 forremoval through the pipe 36, and in part will enter and be retained inthe filter.

The lower portion of the casing 23 forms a grease trap from which adrain pipe 36 extends.

While I have shown and described a preferred apparatus and method forcarrying out the invention, it will be understood that the invention iscapable of variation and modication from the form shown and described sothat the scope thereof should be limited only by the scope of the claimsappended hereto.

I claim:

l. In a ventilator construction for the cooking surface of a kitchenrange, conduit means providing a path of ow of exhaust gases from saidcooking surfaces, means for causing a flow of said gases through saidpath, rotatable means mounted in an upstream portion of said path withrespect to said ow causing means to collect greases therefrom and toeffect a change in the direction of How of said gases from an axial ilowto a general-1y radially outward ow of said gases, said rotatable meansincluding an imperforate interceptor plate extending across said pathwith its periphery spaced inwardly from the inside of said conduit meansso as to deect gases ilovving through said conduit means radiallyoutwardly, said gases then return-owing radially inwardly generally atto their radial outward flow, and a tubular filter of grease entrainingand retaining material carried by said rotatable means on saidinterceptor plate and disposed with its outer surface spaced Iinwardlyfrom the inside of said conduit means whereby gases which have owed.past said interceptor plate along said path and radially outwardly andhave return-flowed radially inwardly generally at 180 =to their radialoutward ow will pass through said lilter from the outside to the insidethereof, drops of grease carried by said return-flow gas being in partrepelled outwardly by the rotating filter and in part entering and beingretained in said filter. Y

2. In a ventilator construction for the cooking surface of a kitchenrange, conduit means providing a path of flow of exhaust gases from thecooking surface, means for causing a ow of gases through said path,means providing an enlarged portion of said path including a housing ina location upstream from said llow causing means, an entrance opening;leading to said housing and dened by a rst annular member, a rotaryblade member having an imperforate top extending over said vopening in 5spaced relation thereto and having a plurality of blades extendingtoward said opening and also directed generally radially outwardlytoward the walls of said housing whereby exhaust gases passing throughsaid entrance opening are deected radially outwardly by said blade 10jecting therefrom and overlapping` saidl second annular 15 2,793,712

member, whereby the exhaust gases passing through said entrance openingand deected outwardly by said blade member toward the walls of saidhousing and then revers- 4 ing their direction through approximately 180will pas radially inwardly through said hollow lter from the outside toinside thereof to reach said exit opening, dropf,` of grease carried byexhaust gas 'wing radially inwardly being in .part repelled radiallyoutwardly by said lter and in part entering and being retained by saidfilter.

References Cited inthe-tile of this patent UNITED STATES PATENTS1,302,716 Sargent May 6, 1,919 2,341,245 Sonntag Feb. 8, 1944 2,392,038Gaylord Ian. l, 1946 2,532,420 Pledger Dec. 5, 1950 2,792,909 Court May2l, 1957 Graswich et al. May 28, 1957 FOREIGN PATENTS 82,993 GermanyIan. 1, 1895

